Quick answer
Determine whether the debt was discharged and whether the contact concerns personal liability or a surviving lien.
Do now
Keep the discharge order, creditor notices, and contact records. Ask your bankruptcy lawyer or the court’s self-help resources about the proper enforcement process. Check whether the obligation was excepted from discharge.
Watch for
Discharge and case closure are different events. A valid lien or nondischargeable debt can require separate treatment; do not assume all post-discharge contact is unlawful.
Official sources
US Courts — Discharge in Bankruptcy, US Courts — Bankruptcy Glossary.